Infrared gas sensor

Abstract

An infrared gas sensor includes: an infrared light source having a resistor for emitting an infrared light by heating the resistor; an infrared light sensor having a detection device for generating an electric signal in accordance with a temperature change of the detection device corresponding to the infrared light in a case where the sensor receives the infrared light; a reflection member for reflecting the infrared light emitted from the light source to introduce the infrared light to the sensor; a casing for accommodating the light source, the light sensor, and the reflection member; and a substrate. The reflection member faces the light source. The resistor and the detection device are disposed on the substrate.

1 . An infrared gas sensor comprising: 
 an infrared light source having a resistor for emitting an infrared light by heating the resistor;    an infrared light sensor having a detection device for generating an electric signal in accordance with a temperature change of the detection device corresponding to the infrared light in a case where the sensor receives the infrared light;    a reflection member for reflecting the infrared light emitted from the light source to introduce the infrared light to the sensor;    a casing for accommodating the light source, the light sensor, and the reflection member; and    a substrate,    wherein the reflection member faces the light source, and    wherein the resistor and the detection device are disposed on the substrate.    
   
   
       2 . The infrared light gas sensor according to  claim 1 , 
 wherein the reflection member is a concave mirror.    
   
   
       3 . The infrared light gas sensor according to  claim 1 , 
 wherein the substrate includes a plurality of membranes as a thin portion of the substrate, and    wherein the resistor and the detection device are disposed on different membranes, respectively.    
   
   
       4 . The infrared light gas sensor according to  claim 3 , 
 wherein the detection device is a thermocouple including a measurement junction and a reference junction,    wherein the measurement junction is disposed on one membrane, and    wherein the reference junction is disposed on the substrate except for the membrane.    
   
   
       5 . The infrared light gas sensor according to  claim 1 , 
 wherein the detection device has a part made of the same material as the resistor.    
   
   
       6 . The infrared light gas sensor according to  claim 1 , 
 wherein the detection device has a part, which is disposed on the same plane as the resistor.    
   
   
       7 . The infrared light gas sensor according to  claim 1 , 
 wherein the substrate is a semiconductor substrate, and    wherein the resistor and the detection device are disposed on the semiconductor substrate through an insulation film.    
   
   
       8 . The infrared light gas sensor according to  claim 1 , further comprising: 
 a circuit chip,    wherein the substrate having the resistor and the detection device is mounted on the circuit chip so that the circuit chip with the substrate is disposed inside the casing.